A detailed study on the scope of the efficient PtCl2-catalyzed synthesis of carbazoles from 1- (indol-2-yl)-2, 3-allenols is described. Through isotopic labeling experiments, it is confirmed that the reaction proceeds through a unique metal carbene intermediate, which undergoes subsequent highly selective 1, 2-hydrogen migration to afford carbazoles. The reaction shows wide scope and allows the introduction of a variety of different substituents at ...